Production of polyalkylstelbene qui-



United States Patent PRODUCTION OF POLYALKYLSTILBENE QUI- NONES AND POLYALKOXYSTILBENE QUI- NONES Joseph A. Chenicek, Bensenville, 111., assignor to Universal Oil Products Company, Chicago, Ill., a corporation of Delaware No Drawing. Application July 20, 1950, Serial No. 175,027

11 Claims. (Cl. 260--396) This invention relates to a process for preparing polyalkylstilbene quinones and polyalkoxystilbene quinones. More particularly, this invention relates to a process for preparing tetraalkylstilbene quinones and tetraalkoxystilbene quinones in which each alkyl and alkoxy group contains from 1 to 6 carbon atoms.

An object of this invention is to produce an organic compound selected from the members of the group consisting of a polyalkylstilbene quinone and a polyalkoxystilbene quinone.

Another object of this invention is to produce a 3,5,3',5- tetraalkylstilbene quinone.

Still another object of this invention is to produce a 3,5 ,3',S -tetraalkoxystilbene quinone.

An additional object of this invention is to produce 3,5 ,3',5 -tetra-tert.-butyl-stilbene quinone.

Still another object of this invention is to produce 3,5,3',5-tetra-methyl-stilbene quinone.

One embodiment of this invention relates to a process for producing a member of the group consisting of a polyalkylstilbene quinone and a polyalkoxystilbene quinone which comprises oxidizing a member of the group consisting of a polyalkylarylamine and a polyalkoxyarylamine in which the alkyl and alkoxy groups contain from 1 to 6 carbon atoms.

Another embodiment of this invention relates to a process for producing a tetra-substituted stilbene quinone in which the substitutents are selected from the members of the group consisting of an alkyl group and an alkoxy group, each containing from 1 to 6 carbon atoms which comprises oxidizing a member of the group consisting of a dialkyl-p-toluidine and a dialkoxy-p-toluidine having alkyl and alltoxy groups containing from 1 to 6 carbon atoms.

Still another embodiment of this invention relates to a process for producing a tetraalkylstilbene quinone which comprises oxidizing "a 2,6-di -alkyl-p-toluidine having alkyl groups containing from Ho 6 carbon atoms.

A further embodiment of this invention relates to a process for producing tetramethylstilbene quinone which comprises oxidizing 2,6-dimethyl-p-toluidine.

A still further embodiment of this invention relates to a process for producing tetra-tert.-butyl stilbene quinone which comprises oxidizing 2,6-di-tert.-butyl-p-toluidine.

Poly-substituted aryl amines of the types indicated by the following equation are oxidized readily to form certain poly-substituted stilbene quinones:

2,733,249 Patented Jan. 31, 195

, in which R and R" represent members of the group consisting of an alkyl group and an alkoxy group, each group having from one to six carbon atoms, and R represents a member of the group consisting of a hydrogen atom, an alkyl group, and an alkoxy group, each group having from one to six carbon atoms.

Thus 2,6-dialkyl-p-toluidine,' 2,6-dialkoxy-p-toluidine, and other aryl amines having the formula indicated in the foregoing equation are oxidized by different means including alkali metal chlorates, ferricyanides, peracids, metal salts, peroxides, lead oxide, silver oxide, and the like. Such an oxidation is carried out, for example, by heating a polyalkylarylamine such as 2,6-dialkyl-p-toluidine at a temperature of from about 20 to about C.

with sodium chlorate and an aqueous solution containing sulfuric acid or another mineral acid.

In another method of effecting such an oxidation, at pentane solution of a 2,6-dialkyl-p-toluidine is contacted with an aqueous solution containing 10% by weight of sodium hydroxide and then this mixture is stirred at a temperature of from about 20 to about 100 C. while an aqueous solution of potassium ferricyanide is added thereto to form a tetraalkylstilbene quinone.

Similar oxidation treatment of a 2,6-dialkoxy-p-toluidine produces a tetraalkoxystilbene quinone. These 2,6- dialkyl-p-toluidines and 2,6-dialkoxy-p-toluidines are also referred to as 2,6-dialkyl-4-methylanilines and 2,6-dialkoxy-4-methylanilines.

T etra-alkylstilbene quinones and tetra-alkoxystilbene quinones which are formed by this process are useful as dyes, germicides, and also as intermediates in the synthesis of other organic compounds and particularly in the synthesis of synthetic sex hormones, plant hormones, and plant growth regulators. These compounds are represented by the following structural formulae:

amtce 1 R2 Ra R wherein each of R1 to Re separately represents a member of the group consisting of hydrogen, alkyl, alkoxy, --NR2, -CH2NR2, and -CH2OR. These compounds are useful as bactericides, fungicides, insecticides, arachnidicides, rodenticides, also as antibacteriological agents, chemotherapeutic agents, antipr'otzoa agents and trypanocidal agents. Some of these compounds are also useful in the control of yeasts, viruses, malaria and other parasites.

Certain examples of the aforementioned tetra-substituted stilbene quinones and their reduction products are Tetra-alkylstilbene quinones can be reduced to form the corresponding 4,4'-stilbene diols and a,a'-dihydrostilbene diols which are useful as synthetic sex hormones and synthetic plant hormones. The tetra-alkylstilbene quinones and tetra-alkoxystilbene quinones are also reduced by catalytic hydrogenation at mild conditions to form di-hydroxy-tetra-alkyl (or tetra-alkoxy)stilbene and dihydrostilbenes which are useful in the syntheses of other organic compounds. Thus 3,5,3',5'-tetra alkyl stilbene quinone and 3.53.5-tetra-alkoxystilbene quinone are hydrogenated to form 4,4'-dihydroxy-3,5,3,5-tetra-alkylstilbcne, 4,4'-dihydroxy-3,5,3',5-tetra-a1koxystilbene, a,adihydro-3,5,3',5 tetra alkylstilbene and u,a dihydro- 3,5,3',5-tetra-alkoxystilbene.

The nature of the present invention is illustrated further by the following example which should not be misconstrued to limit unduly the generally broad scope of the invention.

Mesidine (2,4,6-trimethylaniline also referred to as 2,6- dimethyl-p-toluidine) is oxidized by sodium chlorate in dilute sulfuric acid solution at 70 to 80 C. and by potassium ferricyanide in alkaline solution at 50 to 75 C. to yield among other products a dark red solid, M. I. 221 C., which is 3,5,3',5'-tetra-methylstilbene quinone.

I claim as my invention:

1. A process for producing a poly-substituted stilbene quinone in which the substituents are selected from the members of the group consisting of an alkyl group and an alkoxy group, each containing from one to six carbon atoms, which comprises oxidizing an arylamine with an oxidizing agent at a temperature of from about 20 to about 100 C., said arylamine having the structure:

wherein each of R and R" represents a member of the group consisting of an alkyl group and an alkoxy group each containing from one to six carbon atoms and R represents a member of the group consisting of a hydrogen atom, an alkyl group, and an alkoxy group, each group having from one to six carbon atoms, said oxidizing agent being selected from the group consisting of alkali metal chlorates and alkali metal ferricyanides.

2. A process for producing a polyalkylstilbene quinone which comprises oxidizing a polyalkylarylamine containing at least three alkyl groups and in which each alkyl group contains from one to six carbon atoms with an oxidizing agent at a temperature of from about 20 to about 100 C., said oxidizing agent being selected from the group consisting of alkali metal chlorates and alkali metal ferricyanides.

3. A process for producing a tetraalkylstilbene quinone which comprises oxidizing a 2,6-di-alkyl-p-toluidine having alkyl groups containing from one to six carbon atoms with an oxidizing agent at a temperature of from about C 20 to about 100 C., said oxidizing agent being selected from the group consisting of alkali metal chlorates and alkali metal ferricyanides.

4. A process for producing tetramethylstilbene quinone which comprises oxidizing 2,6-dimethyl-p-toluidine with an oxidizing agent at a temperature of from about 20 to about 100 C., said oxidizing agent being selected from the group consisting of alkali metal chlorates and alkali metal ferricyanides.

5. A process for producing tetra-tert.-butyl-stilbene quinone which comprises oxidizing 2,6-di-tert.-butyl-ptoluidine with an oxidizing agent at a temperature of from about 20 to about 100 C., said oxidizing agent being selected from the group consisting of alkali metal chlorates and alkali metal ferricyanides.

6. A process for producing a tetraalkylstilbene quinone which comprises oxidizing 2,6-dialkyl-p-toluidine having alkyl groups containing from one to six carbon atoms by heating said toluidine with a mixture of an alkali metal chlorate and an aqueous solution of a mineral acid at a temperature of from about 20 to about 100 C.

7. A process for producing a tetraalkylstilbene quinone which comprises oxidizing a 2,6-dialkyl-p-toluidine having alkyl groups containing from one to six carbon atoms by heating said toluidine with a mixture of sodium chlorate and an aqueous solution of sulfuric acid at a temperature of from about to about C. i

8. A process for producing tetramethylstilbene quinone which comprises oxidizing 2,6-dimethyl-p-toluidine by heating said toluidine with a mixture of sodium chlorate and an aqueous solution of sulfuric acid at a temperature of from about 70 to about 80 C.

9. A process for producing tetra-tert.-butylstilbene quinone which comprises oxidizing 2,6-di-tert.-butyl-ptoluidine by heating said toluidine with a mixture of sodium chlorate and an aqueous solution of sulfuric acid at a temperature of from about 70 to about 80 C.

10. A process for producing 3,5,3,5-tetramethylstilbene quinone which comprises oxidizing mesidine by heating in alkaline potassium ferricyanide solution at a temperature of from about 50 to about 75 C.

11. A process for producing a tetraalkoxystilbene quinone which comprises oxidizing a 2,6-dialkoxy-p-toluidine having alkoxy groups containing from one to six carbon atoms with an oxidizing agent at a temperature of from about 20 to about C., said oxidizing agent being selected from the group consisting of alkali metal chlorates and alkali metal ferricyanides.

References Cited in the file of this patent UNITED STATES PATENTS Gibbs Mar. 7, 1944 OTHER REFERENCES 

1. A PROCESS FOR PRODUCING A POLY-SUBSTITUTED STIBENE QUINONE IN WHICH THE SUBSTITUENTS ARE SELECTED FROM THE MEMBERS OF THE GROUP CONSISTING OF AN ALKYL GROUP AND AN ALKOXY GROUP, EACH CONTAINING FROM ONE TO SIX CARBON ATOMS, WHICH COMPRISES OXIDIZING AN ARYLAMINE WITH AN OXIDIZING AGENT AT A TEMPERATURE OF FROM ABOUT 50* TO ABOUT 100* C., SAID ARYLAMINE HAVING THE STRUCTURE: 